Arduino
I'm building an arduino one just now - just needs arduino (3 quid), 433 tx/rx (2 quid).
that's about it - it can then talk to cheap as chips remote power sockets you can pick up on ebay for a fiver.
stick ethernet or wifi board onto arduino (5 quid) and run some a basic webserver on it, and you get all you need to control stuff.
Plus you get the benefit of easily being able to make more complex recievers to do whatever you want - another arduino,433 tx/rx is all you need - plus whatever else you want it to do - mp3 module, relays, stepper motors... the world is yer lobster. It would be relatively trivial to extend the code on your arduino rxs to enable a mesh too if you had a particularily large coverage requirement.
I do also have a raspPi I play with, and I know they are very different fish, but I don't think the arduino gets as much attention as it deserves - even as an educational tool I think it's far more interesting for kids to use and make stuff do things than a raspPi. and much cheaper too.
16Mhz is still a hell of a lot of oomph, and there's very little I've found it can't cope with - for example the most advanced open source automatic flight controller (Arducopter) runs on a 2 quid arduino (plus a few auxiliary sensors).
If anyone is interested in this sort of stuff, I'd urge them to try an ardiuno.